Kajima: Fully automated lining can be used at various locations, reducing costs with vulcanized concrete
March 28, 2025
Admixtures are added to the concrete base on site to make it flow (from press release)
Kajima has developed a low-cost, high-flow concrete for lining that can be cured at the construction site and is using it for the first time in actual construction in conjunction with the existing ``fully automated tunnel lining concrete pouring system''.
Using conventional concrete with a slump of about 15 cm produced at a ready-mixed concrete plant as the base, the concrete is cured using a newly developed admixture on site, significantly reducing production costs compared to factory-made products. By combining with high-flow, in-situ fluid concrete, we have created a fully automated pouring system that can handle tunnel construction work in a wide range of construction conditions and cross-sections.
This system was first introduced at the Yoro Tunnel South Construction Site of the Tokaido Loop Expressway (Inabe City, Mie Prefecture), constructed by Central Nippon Expressway. By liquefying concrete in-situ, the cost of producing high-flow, non-compacting concrete is reduced, and the labor-saving effect of the fully automated pouring system is maximized.
The newly developed high-flow concrete for road lining ensures quality equivalent to factory-made products. An automatic admixture adder is combined with the existing fiber feeder for concrete lining, creating a system in which admixture and fiber are simultaneously fed into the base concrete. The mixture is automatically metered based on the additive and fed from the tank through the nozzle into the mixer truck. The quantity is automatically recorded, reducing the workload of measuring, feeding and management.
A fully automated concrete pouring system was developed in 2020. So far, the scope of use has been expanded from high-flow concrete for lining to medium-flow concrete and has been put into use in two large three-lane tunnel construction projects. By combining it with high-flow concrete cured in place and introducing it into the construction of a two-lane, standard-section tunnel at this site, the system has been perfected to meet a variety of needs.
In the future, the company plans to promote the introduction of new high-flow concrete, aiming to further streamline the construction process.
